In many instances, the method used to bind colorant in a polymer determines the end-use properties of films prepared using the polymer. One of the possibilities to bind colorant with polymer is to react chemically to form a copolymeric colorant. The color polyester compositions using copolymerized anthraquinone colorants are disclosed in U.S. Pat. Nos. 4,267,306, 4,359,570, 4,403,092 and 4,617,373. While the anthraquinone colorants exhibit excellent thermal stability and light fastness, such colorants have the inherent disadvantage of low extinction coefficients and high cost to manufacture.
U.S. Pat. No. 4,477,635 discloses a process for preparing solvent soluble nonextractable copolymeric aminotriarylmethane dye containing polyester, polycarbonate, polyurethane, or polyethyleneimine backbones and incorporating such polymers into resins such as polyvinyl chloride, polyvinylidene chloride and acrylic resins such as poly(methylmethacrylate) etc. by solvent blending techniques. Difficulties are encountered in preparing these copolymeric colored compounds because a noncolored intermediate aromatic amine containing polymer must be prepared and then the aromatic amine moiety in the polymer structure must be converted into the aminotriarylmethane moiety by further reaction with a diaryl ketone in the presence of condensation catalyst such as phosphorous oxychloride in an inert organic solvent.
Attempts to make colored polyester compositions in one step by copolymerizing aminotriarylmethane colorants containing reactive groups have failed because of the thermal instability of the triarylmethane chromophobe. These previously disclosed copolymeric aminotriarylmethane compositions also do not have the requisite thermal stability for use in coloring thermoplastic resins via the more favorable method of melt blending when high temperatures are encountered. These copolymeric colorants are prepared by condensation, polymerization, and are not water-dispersible.
U.S. Pat. Nos. 5,043,376 and 5,104,913 disclose liquid-dispersible colorant compositions prepared by emulsifying water-insoluble copolymeric colorants in the presence of a solvent/or a mixture of solvents and surfactants. The solvent is removed by distillation in order to obtain an aqueous dispersion of the copolymeric colorants. The process requires additional steps to convert water-insoluble copolymeric colorants into water-dispersible form.
U.S. Pat. No. 5,188,641 discloses a process for preparing colored polymer containing repeat units derived from at least one azo dye which is free from water-solubilizing groups and contains at least one polymerizable unsaturated group.
U. K. Patent No. 877,402 discloses a process for preparing colored polymers which are useful as pigments, by copolymerizing azo or anthraquinone dyes containing polymerizable olefinic groups with other unsaturated polymerizable compounds. U.K. Patent Nos. 1,046,751 and 1,218,547 disclose the application of polymerizable dyes containing olefinic groups to textile materials in conjunction with a free radical polymerization initiator with the object of polymerizing the dye on or within the textile fibers. U.K Patent No. 914,354 discloses a process for the simultaneous dyeing and finishing of textiles by applying a colored polymer which has been prepared by the emulsion copolymerization of a dye containing a polymerizable compound, the applied copolymer then being cross-linked.